Sensing device for color tube apparatus



July 5, 1966 J, PEKQSH 3,259,224

SENSING DEVICE FOR COLOR TUBE APPARATUS Filed Aug. 25, 1964 3Sheets-Sheet 1 30a 1 30b FIG. 1 A

i =2 QIF-QD 9 :5 Q1 f QE 51 m FIG. 3 70f I 79 70h I I /"7oe INVENTOR.

: fgaymonci If Pakofih July 5, 1966 R. J. PEKosH 3,

sENsING DEVICE FOR COLOR TuBE'APmRATus Filed Aug. 25, 1964 sSheets-Sheet 2 July 5, 1966 R. J. PEKOSH 3,259,224

SENSING DEVICE FOR COLOR TUBE APPARATUS Filed Aug. 25, 1964 aSheets-Sheet a FIG. 4

United States Patent 3,259,224 SENSING DEVICE FOR COLOR TUBE APPARATUSRaymond J. Pekosh, Chicago, Ill., assignor to The Rauland Corporation,Chicago, 111., a corporation of Illinois Filed Aug. 25, 1964, Ser. No.392,010

8 Claims. (Cl. 19819) The present invention is directed to a system thatis especially suited for controlling cathode-ray tube processingapparatus.

A highly automated apparatus for performing the screening process of atricolor cathode-ray tube is described and claimed in application SerialNo. 391,864, filed concurrently herewith in the name of Joseph P. Fioreand assigned to the same assignee as the present invention. As describedin that application, a multiplicity of workholders are arranged toconvey the cap or screen section of the color cathode-ray tube through aseries of automated work stations where the various processing steps,leading to the deposit of phosphor triads on the screen, are carriedout. To attain maximum efficiency, these stations are programmed toperform their various assignments automatically when a workholder hasbeen brought to a stop within each such station. If for any reason aWorkholder should be presented to these stations without having the capor screen section of a tube positioned within it, there would be anundesirable dispersion of materials within the apparatus unlessprovision were made to interrupt the work function of any such stationwhich is called upon to perform its process in the presence of aworkholder that does not bear the cap section of a color cathode-raytube. The present invention addresses itself to this problem andprovides a control system to obviate such undesired results. It is,therefore, a principal object of the invention to provide a system forcontrolling the processing apparatus for cathode-ray tubes.

It is :a specific object of the invention to provide a system forcontrolling the processing functions of a screening apparatus for colorcathode-ray tubes.

Another specific object of the invention is to provide a control systemwhich permits the screening apparatus in a color tube plant to performits functions only when there has been presented a tube section orcomponent upon which the work may be conducted. The control is on aper-station basis and the work function is interrupted at only thosestations which do have a tube component for processing.

Accordingly, the control system of the invention is associated with acathode-ray tube processing apparatus having a conveyor which transportsa multiplicity of workholders through a plurality of work stations. Thecontrol system comprises a probe for sensing the presence of acathode-ray tube component within a workholder. The probe is supportedadjacent the conveyor and is movable from a rest position to a fullyactuated position which it may assume only if the workholder beingsensed does not contain a cathode-ray tube component. An actuatoryieldably advances the probe from its rest position toward its actuatedposition. There are means for energizing this actuator in timed relationto the movement of the conveyor in order to effect sensing of theworkholders by the probe on an individual basis. There is a controlmember for each of the workholders, movable with the conveyor ice anddisplaceable into a position to control the processing functionconducted in at least one, but preferably in all, of the automated workstations. Finally, there are means, responsive to the position attainedby the probe during sensing, for determining the position of the controlmember associated with the workholder instantaneously sensed by theprobe.

The features of the present invention Which are believed to be novel areset forth with particularity in the appended claims. The invention,together with further objects and advantages thereof, may best beunderstood by reference to the following description taken in connectionwith the accompanying drawings, in the several figures of which likereference numerals identify like elements, and in which:

FIGURE 1 is a plan view of a screening layout for depositing phosphordots on the screen section of a color cathode-ray tube;

FIGURE 2 is a view, partially broken away, showing structural details ofone of the conveyors of FIGURE 1;

FIGURE 3 is a top view of the control member or flag of a screening cartfor the conveyor of FIGURE 1; and

FIGURES 4-6 are detailed views of the control arrangement of theinvention for sensing the workholders of the screening carts included inthe screening conveyor.

The layout of FIGURE 1 represents screening apparatus for applyingdeposits of phosphor to the end cap or screen section of a colorcathode-ray tube. It illustrates the same type arrangement as describedin the Fiore -appli-. cation but simplified to show merely two screeningconveyors and one light-exposure conveyor. These components cooperate inlaying down one family of phosphor dots on the tube screen although acomplete screening arrangement deposits three similar and interlacedfamilies of phosphor dots characterized by emitting radiations of green,blue and red in response to the impingement of a cathode-ray beam. Sincethe control system of the present invention may be completely understoodfrom consideration of so much of the screening plant as deposits thegreen phosphor dots, the illustration of FIGURE 1. has been confinedaccordingly. Reference may be had to the Fiore application for adisclosure of the screening arrangement in its entirety.

The screening apparatus, as shown, comprises two similar endlessconveyors 30a and 30b, individually in the form of a closed, elongatedloop arranged in alignment with their longitudinal axes in parallelrelation with one another. Each such conveyor has a series of screeningcarts having workholders for individually supporting the screen sectionof a color television tube and for transporting the screen from aloading station through a multiplicity of screen processing stations toa discharge station of that conveyor. The small rectangles 31 representthe screening carts of each conveyor and each such cart has its ownworkholder as will be described more particularly hereinafter. Thirtysuch carts are represented in each of, the screening conveyors and theconveyors each have an intermittent or step-by-step indexed type ofdrive from which it may be said that there are 30 stations on eachconveyor devoted to loading, work processing and discharge or un-,

loading. The lettered circles depict specific ones of these stations andsimilar designations as between the several conveyors designate likestations from the standpoint of manipulation or work process conducted.The following table assigns for each station the process step that takesplace, the angle of the axis of rotation of the tube screen in thatstation relative to vertical and the speed of rotation of the screenabout its central axis, that is to say, the axis that corresponds to thelongitudinal axis of the tube into which the screen is ultimatelyassembled. The details by which varying speeds and varying angles oftilt are imposed on the work table are of no consequence to the presentinvention and are explained in the Fiore application.

The cross-hatching of the screening conveyors 30 in FIGURE 1 representsa housing of vertical walls and because of the housing the sides of eachconveyor loop are enclosed. It is desirable, of course, that theenclosing walls be transparent at least in part to permit observation ofthe work functions being carried out. The end portions of each conveyorloop, however, are exposed because the operations performed there aremanual, namely, those of loading, unloading and inspection.

In addition to screening conveyors 30 there is shown an endless conveyor32, referred to as a merry-go-round, having a loading station Q and adischarge or unloading station R. The merry-go-round is positioned withits terminal stations Q, R displaced between and adjacent the endportions of screening conveyors 30a, 30b to the end that the dischargestation M of screening conveyor 30a is in close physical proximity toloading station Q of merry-goround station 32. Moreover, dischargestation R of this merry-go-round is similarly located in close proximityto loading station A of screening conveyor 30b.

The merry-go-round has a series of light-exposure housings 33 popularlyreferred to as exposure carts, the details of which are of no particularconcern to the subject invention. Suflice it to say that each cartsupports and selectively exposes predetermined portions of aphotosensitive coating which has previously been deposited on the tubescreen section accommodated by a particular cart. The exposure isaccomplished as the merry-go-round transports that exposure cart with ascreen section from the loading station of the merry-go-round to itsdischarge station. Of course, the photosensitive resist materials whichare normally deposited along with the phosphor coating material on thescreening conveyor have a predetermined development time and the speedof the merry-go-round is preferably -adjusted so that the travel fromload to discharge'takes at least this same amount of time. It is alsodesirable to relate the movement of the merry-go-round to the movementof the screening conveyors. Since a series of discrete processing stepsof very different types are carried out in the many stages of eachscreening conveyor, it is most convenient that the screening conveyorshave an intermittent or step-by-step drive represented as unit 45 inFIGURE 2. Such driving mechanisms which step a conveyor intermittentlyunder the control of a programming arrangement are well known in theart. The details of the intermittent drive and the programmingarrangement constitute no particular part of the subject invention and,therefore, have not been disclosed in detail.

It is preferred that the merry-go-round have an effective index timethat is related to the index time of the screening conveyors with whichit is associated. The eifective index time of the merry-go-round is thetime required for an exposure cart to travel from a given point indischarge station R to the corresponding point in loading station Q. Inparticular, the exposure cart preferably advances from its discharge toits loading station in a time equal to or less than the index time ofthe screening conveyors. This may be easily accomplished by having acontinuous motor drive for the merry-go-round with a gear reductionsystem to attain the requisite speed of the exposure housings. When theindex time of the merry-go-round is less than that of the screeningconveyor, it should be divisible equally into the screening conveyorindex time. For example, the merry-go-round indexing may be twice asfast as that of the screening conveyor.

Overall operation In considering the overall operation of the describedarrangement, it will be understood that it is essential to maintain asclean an atmosphere and environment as practicably possible.Accordingly, the conveyors are housed in a room that is kept clean andhas carefully protected entrances to preserve its cleanliness. Thepreferred apparatus and arrangement for maintaining an essentially cleanenvironment for the work stations of the screening conveyors is thesubject of an application filed concurrently herewith in the name ofJoseph P. Flore et al., Serial No. 391,985, assigned to the sameassignee as the present invention. It is sutficient to say that theportions of the screening conveyors 30 that are enclosed by the housingof the conveyor are constantly bathed in a controlled stream or flow ofprecisely conditioned air.

Each screening conveyor is driven in the direction indicated by thearrows by a conventional index type of intermittent or step-by-stepdrive. It has been found that an index interval of approximately 28 to30 seconds is adequate.

It is also preferred that interlocks be provided at any station where,in conducting the work assigned to that station, mechanism of any kindis advanced into the path of travel of the screening carts or the screensections mounted thereon. The interlock may take the simple form of amicroswitch which in its open condition causes the index drive of theconveyor to be interrupted but the microswitch is closed by the returnof the movable components of the working station to their normal or restpositions clear of the path of travel of the screening car-ts and thescreen sections under process. Illustrative use of the interlock switchwill be described hereafter but it is not believed necessary to show theelectrical system of the index drive incorporating the protection of theinterlocks. Their association would be essentially that of a seriescircuit, requiring all interlocks to be closed before the indexingcircuit is permitted to perform.

Merry-go-round 32 rotates continuously in the direction indicated by thearrow and at a speed to correlate lighthouse loading to screen conveyorunloading as described above.

In operation, the screen sections to be processed are delivered toloading station A of screening conveyor 30a by a conveyor feeding in thedirection of arrow 34a. As color tubes are currently made, the screensection is the cap of the envelope with a surface to bear the phosphorsand a peripheral flange through which the screen section may beintegrated with the funnel and neck section by a sealing process. It hasbeen determined that optimum results are attained through the practiceof pairing by which is meant that each screen employs its own shadowmask as an exposure device in the screening process and, therefore, eachcap delivered to the screening room has its mask along with it.

The operator loads a screen section onto a screening cart at station Aof conveyor 30a and also loads its mask on the same screening cart. Theconveyor then indexes to position B where the cart is sensed todetermine whether or not it bears a screen; if it does, that cart willproceed through the work stations and the screen which it carries willreceives the various processing steps. On the other hand, if thescreening cart does not carry a screen section, a control to bedescribed later is accomplished which disables the function of thevarious work stations as this particular cart passes through.

Assuming that the screening cart to be followed through the conveyor byway of illustration does have a screen section, after leaving sensingstation B, it advances to stations C where it is detergent washed by ahigh velocity spray and is then rinsed at station D with warm deionizedwater. The screen is subjected to a spray of polyvinyl alcohol atstation E. In the next stations F, the panel is dried by infraredheaters which may be positioned on the wall sections enclosing theconveyor. At station G, cooling is initiated and a fan may be employedto direct conditioned air, which is bathing these stations, moreparticularly into the screen section. Further cooling is accomplished atstation H and the screen is manually inspected at stations I. If anydefect is observed, the screen is unloaded and its cart is manuallyadjusted to disable the automatic processing apparatus at subsequentstations but only while this cart is present in any such station. On theother hand if the screen passes inspection, it continues through thework stations on the other side of the conveyor. Station H is forfurther cooling and at station B a further sensing operation takesplace. Sensing at this station is a mere precaution and may be omitted,relying on the inspector to adjust any screening cart which has carrieda screen section that failed to pass inspection.

At station I, a charge of slurry is deposited on the screen. This slurrycontains green phosphor material as well as a photosensitive resist andthe rotation of the workholder on the screening cart distributes theslurry evenly across the entire screen section. At the next station K, aprobe in the form of a cylindrical tube is lowered into the rotatingscreen to collect or reclaim excess slurry, the slurry being displacedinto the tube through centrifugal force and gravity and returned to areservoir in a closed circulating system.

After preliminary drying at station F with infrared heaters, the capadvances to station L where a trim probe is introduced over the skirt ofthe panel. The trim probe is a water jet which cuts the slurry depositjust above the meeting line of the screen and its peripheral flange.Following the trim step, the panel is further dried at stations F andcooled in the final stations H from which it advances to dischargestation M.

The screen section with its mask has now completed a traverse of thefirst screening conveyor and is ready for exposure. The mask is firstpositioned within the, screen section and the assembly is removed fromconveyor 30a and placed on the exposure cart instantaneously at loadingstation Q of merry-go-round 32.

Since the cap to be exposed on merry-go-round 32 bears a coatingcontaining green phosphor, the light source in each cart of thatmerry-go-round is positioned to simulate the location of the green gunin the finished tube,

assuming that the process is directed to the production of a three-gunshadow mask tube. The screen section under consideration is subject toexposure in its cart in order to locate the dots of green phosphor onthe screen. Each cart has its own timing device which may be achronometer or may be a light integrator. The first maintains anexposure for a fixed period of time .and the latter maintains anexposure sufiicient to achieve a desired total integration of incidentlight. Generally, operating times can be established that permit use ofa timing or clock mechanism on the exposure cart. The clock mechanismremoves a shutter from the lightpath of a high pressure mercury lamp asthe cart leaves loading station Q and returns the shutter to block thatlightpath after the selected exposure interval which will be no more,and generally less, than the time required for this lighthouse to arriveat discharge station R. The exposed screen section with its mask,through which it has been exposed, is now removed from the cart andloaded onto the screening cart at station A of screening conveyor 30b.Of course, the mask is removed from the panel and stored on thescreening cart, leaving the panel free for further processing.

Generally, the same steps are carried out on screening conveyor 30bexcept that the pass from the loading station A to inspection station Iis devoted to developing of the green dots. In developing stations N, aspray of warm deionized water, carefully controlled as to pressure,temperature and pattern, removes all except the exposed portions of thephosphor coating that had been applied to the screen on the precedingconveyor 30a. This results from the fact that the exposure of thephotoresist in the exposure cart causes the desired dots to be insolublein Water whereas the unexposed portions of the coating remain solubleand, therefore, they wash off at stations N. Concurrently, a waterstream directed at the flange of the screen section removes any unwantedresidue of green phosphor coating.

The inspector at station I determines whether or not a satisfactorypattern of green dots has been laid down on the screen. If not, thatscreen is rejected; otherwise, it proceeds down the other side ofconveyor 30b and undergoes essentially the same processing steps as tookplace in its travel through the corresponding portion of the precedingconveyor. This time, however, the coating includes a blue, rather than agreen, phosphor.

It is not necessary to continue the description of the process steps fordeveloping the families of blue and red phosphor dots. They aregenerally similar to those previously describe-d.

It is desirable to consider certafn details of screening conveyors 39 inorder to develop the environment of the control system of the presentinvention which determines Whether or not work functions are carried outin the various automated stations of the conveyor. As shown in FIGURE 2,the conveyor is structurally supported from the floor 39 of thescreening room and the movable mechanism of the conveyor comprises twolink chains 41, 41a concurrently driven by sprocket wheels 43, 43a. Thechains themselves are of conventional construction. The drive of thesprocket wheels is from a motor 44 through an indexed intermittent drive45 designed to rotate each gear in each step of the index program. Boththe upper and lower conveyor chains have provisions through which manyscreening carts are mounted thereto. As shown, the screening cart 70 hasa mechanical connection 79a with the upper conveyor chain and anothermechanical connection 761) with the lower chain. Preferably and asdescribed in the Fiore application these are removable connections tofacilitate removing the screening cart 70 from the convey-or.

Details of screening cart '70 are disclosed and claimed in anapplication, Serial No. 391,985, filed concurrently herewith in the nameof Joseph P. Fiore et a1. and, likewise, assigned to the same assigneeof the present invention. It is only necessary here to understand thateach screening cart 70 has a workholder 73 by means of which the screensection 26 of a color cathode-ray tube is conveyed through the screeningmachine. This screening arrangement contemplates pairing which entailsthe use of an aperture mask in developing the family'of phosphor dots onscreen section 26. Accordingly, each screening cart also accommodatesthe mask 25 associated with the cap section 26 that is being processed.The workholders are of the open-frame type being formed of a spider ofthree arms, two of which appear in FIGURE 2. The arms have .adisplacement of about an axis of rotation and the workholder is mountedon screening cart 70 to be rotated at a controlled'speed. While themechanical drive for the workholder is fully described in the Fiore etal. application, it is of no concern to the present invention.

There is a control member for each workholder movable with the conveyorand displaceable into a position to control the processing functionconducted in at least one, but preferably in all, of the automated workstations of the screening conveyor. This control member 700, usuallyreferred to as a flag, is shown in FIGURE 3. It is an overcenterarrangement of springs 70 which causes the flag to be a two-positiondevice. The flag has a pivot pin 70g rotatably secured between fingers7011 which are integral parts of screening cart 70. Forwardly of pin 70gthe flag carried an anchor pin 7tlj for springs 70 This is a wellrecognized overcenter construction and permits the flag to have twodiscret positions, one above and the other below the plane of pivot pin70g.

Sensing Obviously, if a screening cart should go through the variouswork stations of any screening conveyor without carrying a cap or screensection 26 to be Worked upon, there would be both a waste and a highlyundesirable dispersion of slurry and fluids on the conveyor. In order toavoid any such undesirable result, and in accordance with the invention,each screening conveyor has a control system which determines whether ornot the work process is to be carried out at the various stations,

The control system comprises a probe for sensing the presence of a tubecap within the workholder. Referring to FIGURES 4-6 which represent thecontrol system, a plurality, specifically two, probes 80, 80 areprovided being slidably mounted within a frame 800 of U-shapedconfiguration with its arms apertured to accommodate probes 80. Asindicated in FIGURE 4, the probes are supported adjacent the screeningconveyor and in particular adjacent the lowermost portion of workholder73 here shown in the angular relation that it assumes in sensing stationB of each screening conveyor. The slidable mount for the probes permitsthem to be movable from a rest position shown in full-construction linein FIGURE 4 to a fully actuated position designated by thebroken-construction line in the same figure which either probe mayassume only if the workholder being sensed does not contain acathode-ray tube component, specifically, a cap or screen section 26.

In order to accomplish their sensing function, the probes may bedisplaced by an actuator which yieldably advances the probes from theirrest toward their fully actuated positions. The actuator illustratedincludes an air cylinder 80b having a piston Site with a rod 8ldmechanically connected to a flange of member 80a. A pair of guide rodsSile, positioned on opposite sides of and in parallel relation to theair cylinder and its piston, extend through apertures of member 80a andprovide rails upon which that member may readily slide under theinfluence of piston 80 as it is displaced within its cylinder. Theserods are supported on a stationary frame 79. Piston displacement isaccomplished in the usual way of a hydraulic motor by means of an airvalve 80 which may be operated to displace the piston to the right asviewed in FIGURE 4 and by a second air valve 805; operated to restorethe piston to a rest position, retracting the probes from the path ofthe workholders. While there is a positive connection between member 80aand piston rod 80d, the coupling to the probes is a yieldable oneafforded by coil springs 8011 which are concentrically arranged relativeto the probes. At one end each of the springs abuts a flange of member80a and at their opposite ends they engage a washer or other stopelement Sfij mechanically connected to each probe.

There is need of means for energizing the hydraulic actuator in timedrelation to the movement of the screening conveyor to effect sensing ofthe workholders, one at a time, by probes 80. The actuator might readilybe energized by a trip to be engaged by a workholder as it approachesstation B but it is just as convenient to include a control circuitwithin indexing control system 45 to time the operation of valves and80g in a desired sequence relative to the entry and departure of aworkholder from sensing station B.

The information obtained from sensing of the workholder is utilized todisplace a control member provided for each of the workholders anddisplaceable into a position to control the processing functionconducted in at least one of the work stations of the conveyor butpreferably controlling the work functions in all of the automatedstations of the conveyor. The control member on each screening cart isthe element or flag 70e described hereinbefore in relation to FIGURE 3.With reference to FIGURE 3, the flag travels in the direction indicatedby an arrow as the screening cart is advanced with the conveyor. Withthe flag in its rest position, it passes above the level of amicroswitch '79 located at each automated work station to control itsprocess. On the other hand, if the flag has been displaced into itsactuated or effective position, it bears against microswitch 79 as thescreening cart moves along, closing the switch to initiate the workfunction at this automated station.

There are means to establish flag 70a in its rest position prior to theentry to station B of the screening cart with which it travels. Again,this function may be accomplished from the programming system of index45 but it is just as convenient in this case to arrange a cam block 80k(FIGURE 2) on the frame of the screening conveyor in the path of flag70a mechanically to displace the flag to its rest position after thescreening cart leaves the final processing station.

Additionally, the control system has means, responsive to the positionattained by probes 80 during sensing, for determining the position offlag 70s. This control means has a pair of switches Sill having a switchoperator 80m in alignment with each of the probes for actuation thereby.As indicated in FIGURE 6, switches 80! are series connected in a controlcircuit for energizing a solenoid 8t). Energization of the solenoiddisplaces its armature which moves flag 70e from its rest position (FIG-URE 6) to its actuated position.

It is prudent to provide an interlock at the sensing station so thatindexing of the conveyor may only take place if the sensing operationhas been completed and the probes restored to their rest position ofFIGURE 4. Such an interlock is represented at 80p. It is a microswitchincluded in the programming drive control of the conveyor and,physically, it is in the path of an abutment 801' on member 80a whichcloses switch 80p when that member has been returned to its homeposition.

In operation, the programming system of index 45 operates valve 80 toadvance probes 80 toward a workholder after that workholder has beenstopped in sensing station B. Since the workholder has a frame orspiderlike structure, the pair of probes, displaced relative to oneanother in the direction of movement of the conveyor, is a precautionagainst the possibility that a single probe may engage the workholderrather than sensing for a screen cap 26 within the workholder.

As piston 86d advances to the right, displacing member 80a in the samedirection, the probes move from their rest toward their fully actuatedpositions. If the workholder does, in fact, contain a tube cap, bothprobes engage the cap in normal operation as represented in FIGURE 5.This arrests their further movement prior to the complete travel ofpiston 80d to the right. As a consequence, in the continued movement ofmember 80a by the air cylinder the switch operators 80m are engaged bythe ends of probes 86. The switch operators may conveniently terminatein rollers which roll up upon the probes, rotating the switch operatorsand closing the switches. If both are closed, solenoid 801i is actuatedand flag 70s of the screening cart is moved to its operative position.Immediately thereafter valve 80g operates to restore the mechanism tothe position shown in solid outline in FIG- URE 4. In so doing, itcauses abutment 80r to close microswitch 80b and permit the indexing ofthe conveyor to continue.

In case the workholder does not, in fact, contain a tube cap, at leastone of probes'80 is permitted to advance to its fully actuated position.In such case, the switch operator 80m associated with that probe is notactuated; the energizing circuit of solenoid 80n is not completed andflag We is retained in its rest position. Accordingly, the furtherprogress of the screening cart through the conveyor does not occasionactuation of the automated work processing apparatus in the variousstations.

While particular embodiments of the invention have been shown anddescribed, it will be obvious to those skilled in the art that changesand modifications may be made without departing from the invention inits broader aspects, and, therefore, the aim in the appended claims isto cover all such changes and modifications as fall within the truespirit and scope of the invention.

I claim:

1. In cathode-ray tube processing apparatus having a conveyortransporting a multiplicity of workholders through a plurality of workstations, a control system comprising:

a probe, for sensing the presence of a cathode-ray tube component withina workholder, supported adjacent said conveyor and movable from a restposition to a fully actuated position which it may assume only if theworkholder being sensed does not contain a cathode-ray tube component;

an actuator for yieldably advancing said probe from said rest positiontowards said actuated position;

means for energizing said actuator in timed relation to the movement ofsaid conveyor to effect sensing of one of said workholders by saidprobe;

a control member for each of said workholders, movable with saidconveyor, and displaceable into .a position to control the processingfunction conducted in at least one of said work stations;

and means, responsible to the position attained by said probe duringsensing, for determining the position of the control member associatedwith the workholder instantaneously sensed by said probe.

2. In cathode-ray tube processing apparatus having a conveyortransporting a multiplicity of workholders through a plurality of workstations, a control system comprising:

a plurality of probes, for sensing the presence of a cathode-ray tubecomponent within a workholder, supported adjacent said conveyor andindividually and independently movable from a rest position to a fullyactuated position to a fully actuated position which each may assumeonly if the workholder being sensed does not contain a cathode-ray tubecomponent;

an actuator for yieldably advancing said probes simultaneously from saidrest position towards said actuated position;

means for energizing said actuator in timed relation to the movement ofsaid conveyor to effect sensing of one of said workholders by saidprobes;

a control member for each of said workholders, movable with saidconveyor, and displaceable into a position to control the processingfunction conducted in at least one of said work stations;

and means, responsive to the positions attained by said probes duringsensing, for determining the position of the control member associatedwith the workholder instantaneously sensed by said probes.

3. In cathode-ray tube processing apparatus having a conveyortransporting a multiplicity of open frame workholders through aplurality of work stations, a control system comprising:

a plurality of probes, for sensing the presence of a cathode-ray tubecomponent within a workholder, spaced from one another in the directionof travel of said workholders, supported adjacent said conveyor andindividually and independently movable from a rest position to a fullyactuated position which each may assume only if the workholder beingsensed does not contain a cathode-ray tube component;

an actuator for yieldably advancing said probes simultaneously from saidrest position towards said actuated position;

means for energizing said actuator in timed relation to the movement ofsaid conveyor to effect. sensing of one of said workholders by saidprobes;

a control member for each of said workholders, movable with saidconveyor, and displaceable into a position to control the processingfunction conducted in at least one of said work stations;

and means, responsive to the positions attained by said probes duringsensing, for determining the position of the control member associatedwith the workholder instantaneously sensed by said probes.

4. In cathode-ray tube processing apparatus having a conveyortransporting a multiplicity of open'frame workholders through aplurality of work stations, a control system comprising:

a plurality of probes, for sensing the presence of a cathode-ray tubecomponent within a workholder, spaced from one another till thedirection of travel of said workholders, supported adjacent saidconveyor and individually and independently movable from a rest positionto a fully actuated position which each may assume only if theworkholder being sensed does not contain .a cathode-ray tube component;

an actuator for yield-ably advancing said probes simultaneously fromsaid rest position towards said actuated position;

means for energizing said actuator in timed relation to the movement ofsaid conveyor .to eflect sensing of one of said workholders by saidprobes;

.a control member for each of said workholders, movable with saidconveyor, and displaceable into a position to control the processingfunction conducted in at least one of said work stations;

a plurality of switches individual-1y 'actuable between open and closedconditions in accordance with .the position attained by an assigned oneof said probes during sensing;

and a control circuit including said switches in series for determiningthe position of the control member associated with the workholderinstantaneously sensed .by said probe.

5. In cathode-ray tube processing apparatus having a conveyortransporting a multiplicity of workholders through a plurality of Workstations, a control system comprising:

a probe, for sensing the presence of a cathode-ray tube component withina workholder, supported adjacent said conveyor and movable from a restposi- -tion to a fully actuated position which it may assume only if theworkholder being sensed does not contain a cathode-ray (tube component;

an actuator for yieldably advancing said probe from said rest positiontowards said actuated position;

means for energizing said actuator in timed relation :to the movement ofsaid conveyor to effect sensing of one of said workholders by saidprobe;

a control member for each of said workholders, movable with saidconveyor, and displaceable into a position to control the processingfunction conducted in at least one of said work stations;

at least one switch associated with said probe to assume an opencondition when said probe advances .to its fully (actuated position andotherwise to assume a closed position;

and a control circuit including said switch for determining the positionof the control member associated with the workholders instantaneouslysensed by said probe.

6. In cathode-ray tube processing apparatus having a conveyortransporting a multiplicity of workholders through a plurality of workstations, a control system comprising:

a probe, for sensing the presence of a cathode-ray tube component Withina workholder, supported adjacent said conveyor and movable from a restposition to a fully actuated position which it may assume only if theworkholder being sensed does not contain a cathode-ray tube component;

an actuator for yieldably advancing said probe from said rest positiontowards said actuated position;

means for energizing said actuator in timed relation to the movement ofsaid conveyor to effect sensing of one of said workholders by saidprobe;

a control member for each of said workholders, movable with saidconveyor, anddisplaceable from a rest position into an actuatedposit-ion in which it is effective to initiate the work functionconducted in at least one of said work stations along the conveyor pathsubsequent .to the location of said probe;

at least one switch associated with said probe to as sume an opencondition when said pro-be advances to its fully actuated position andotherwise to assume a closed position;

and a control circuit including said switch for displacing to itsaforesaid actuated position the control member associated with theworkholder instantaneously sensed by said probe.

7. In cathode-ray tube processing apparatus having a conveyortransporting a multiplicity of workholders through a plurality of workstations, a control system comprising:

a probe, for sensing the presence of a cathode-ray tube component withina workholder, supported adjacent said conveyor and movable from a restposition to a fully actuated position which it may assume only if theworkholder being sensed does not contain a cathode-ray tube component;

an actuator for yieldably advancing said probe from said rest positiontowards said actuated position;

means for energizing said actuator in timed relation to the movement ofsaid conveyor to effect sending of one of said workholders by saidprobe;

a control member for each of said workholders, movable with saidconveyor, and \displaceable from a rest position into an actuatedposition in which it is effective to initiate the work functionconducted in at least one of said work stations along the conveyor pathsubsequent to the location of said probe;

means for establishing the control member of each workholder to its restposition as its assigned workholder approaches the location of saidprobe;

at least one switch associated with said probe .to assume an opencondition when said probe advances to its fully actuated position andotherwise to assume a closed position;

and a control circuit including said switch for displacing to itsaforesaid actuated position the control member associated with theworkholder instantaneously sensed by said probe.

8. In cathode-ray tube processing apparatus having a conveyortransporting a multiplicity of workholders througha plurality of workstations, a control system compnsmg:

a probe, for sensing the presence of a cathode-ray tube component withina workholder, supported adjacent said conveyor and movable from a restposition :to a fully actuated position which it may assume only if theworkholder being sensed does not contain a cathode-ray tube component;

an actuator for y-ieldably advancing said probe from said rest positiontowards said actuated position and tor returning said probe to its restposition;

means for energizing said actuator in timed'relation to the movement ofsaid conveyor to effect sensing of one of said workholders by saidprobe;

a control member for each of said work-holders, movable with saidconveyor, and displaceable from a rest position into an actuatedposition in which it is effective to imitate the work function conductedin at least one of said work stations along the conveyor path subsequentto the location of said probe;

means for establishing the control member of each workholder to its restposition as its assigned workholder approaohes the location of saidprobe;

at least one switch associated with said probe to assume an opencondition when said probe advances to its fully actuated position andotherwise to assume a closed position;

a control circuit including said switch for displacing to its aforesaidactuated position the control member associated with the workholderinstantaneously sensed by said probe;

a driving system for said conveyor for advancing said workholders stepby step through said work stations;

.an interlock switch .to be closed to energize said driving system;

and .a switch operator movable with said probe for closing saidinterlock switch when said probe is in its aforesaid rest position.

References Cited by the Examiner UNITED STATES PATENTS 2,376,980 5/1945Petersen 1182 SAMUEL F. COLEMAN, Primary Examiner.

E. A. SROKA, Assistant Examiner.

1. IN CATHODE-RAY TUBE PROCESSING APPARATUS HAVING A CONVEYORTRANSPORTING A MULTIPLICITY OF WORKHOLDERS THROUGH A PLURALITY OF WORKSTATIONS, A CONTROL SYSTEM COMPRISING: A PROBE, FOR SENSING THE PRESENCEOF A CATHODE-RAY TUBE COMPONENT WITHIN A WORKHOLDER, SUPPORTED ADJACENTSAID CONVEYOR AND MOVABLE FROM A REST POSITION TO A FULLY ACTUATEDPOSITION WHICH IT MAY ASSUME ONLY IF THE WORKHOLDER BEING SENSED DOESNOT CONTAIN A CATHODE-RAY TUBE COMPONENT; AN ACTUATOR FOR YIELDABLYADVANCING SAID PROBE FROM SAID REST POSITION TOWARDS SAID ACTUATEDPOSITION; MEANS FOR ENERGIZING SAID ACTUATOR IN TIMED RELATION TO THEMOVEMENT OF SAID CONVEYOR TO EFFECT SENSING OF ONE OF SAID WORKHOLDERSBY SAID PROBE; A CONTROL MEMBER FOR EACH OF SAID WORKHOLDERS, MOVABLEWITH SAID CONVEYOR, AND DISPLACEABLE INTO A POSITION TO CONTROL THEPROCESSING FUNCTION CONDUCTED IN AT LEAST ONE OF SAID STATIONS; ANDMEANS, RESPONSIBLE TO THE POSITION ATTAINED BY SAID PROBE DURINGSENSING, FOR DETERMINING THE POSITION OF THE CONTROL MEMBER ASSOCIATEDWITH THE WORKHOLDER INSTANTANEOUSLY SENSED BY SAID PROBE.